We report on the rare eruption of a miniature Ha filament that took the form of a surge. The filament first underwent a full development within 46 min and then began to erupt 9 min later, followed by a compact, impulsive X-ray class M2.2 flare with a two-ribbon nature only at the early eruption phase. During the eruption, its top rose, whereas the two legs remained rooted in the chromosphere and showed little swelling perpendicular to the rising direction. This led to a surge-like eruption with a narrow angular extent. Similar to the recent observations for standard and blowout Xray jets by Moore et al., we thus define it as a "blowout Ha surge." Furthermore, our observations showed that the eruption was associated with (1) a coronal mass ejection guided by a pre-existing streamer, (2) abrupt, significant, and persistent changes in the photospheric magnetic field around the filament, and (3) a sudden disappearance of a small pore. These observations thus provide evidence that a blowout surge is a small-scale version of a large-scale filament eruption in many aspects. Our observations further suggest that at least part of the Ha surges belong to blowout-type cases, and the exact distinction between the standard and blowout Ha surges is important in understanding their different origins and associated eruptive phenomena.

项目资助者

National Basic Research Program of China (973 program) [2011CB811400]
; National Natural Science Foundation of China [10973038, 11173058]